Poster: Integrative plant physiology

Abs # 40: Analysis of an abscission-associated cellulase in Arabidopsis

Presenter:	Thoma, Sharon L, sthoma@edge.edu
Authors	Thoma, Sharon L (A)   Most, Ayala  (B)   Glass, Tiffany  (C)   Biller, Josh  (A)   Patterson, Sara  (B)
Affiliations:	(A): Department of Natural Science, Edgewood College (B): Department of Horticulture, University of Wisconsin (C): Department of Medicine, John Hopkins University

Abscission is regulated cell separation resulting in the detachment of organs. This occurs during specific stages of development or in response to environmental signals. During the process of abscission, there is an increase in the expression of cell wall hydrolytic enzymes, including cellulases (beta-1,4 endo-glucanases). We have screened the Wisconsin T-DNA collection and the SALK collection to identify knockouts in abscission-associated cellulases. We will present characterization of one of these mutants (cel3). The mutants do not have a delayed abscission phenotype, and SEM analysis shows no clear anatomical abnormalities in the floral organ abscission zones. Petal break strength is not significantly altered in the mutant plants. Consequently, we have also looked at other cell separation processes during development. Using RT-PCR and in situ hybridization we have observed differential expression of CEL3 in various tissues and in the five stages of floral organ abscission. Our analysis indicates that this gene is involved in regulating abscission and cell separation in specific tissues; however, the lack of a clear phenotype illustrates predicted overlapping functions of the many members of this gene family. This work was funded by USDA grant 0035301-9085 and NSF plant genome research and REU program.